Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Use Fields
POLYGONSELECTIONTAG_ENABLEFIELDSParameter: Restore Selection
POLYGONSELECTIONTAG_COMMAND1Parameter: Select Polygons
POLYGONSELECTIONTAG_COMMAND3Parameter: Hide Polygons
POLYGONSELECTIONTAG_COMMAND5Parameter: Select and Hide Others
POLYGONSELECTIONTAG_COMMAND2Parameter: Deselect Polygons
POLYGONSELECTIONTAG_COMMAND4Parameter: Unhide Polygons
POLYGONSELECTIONTAG_COMMAND6Parameter: Tolerance
POLYGONSELECTIONTAG_FIELDTOLERANCEParameter: Use Deformed Points
POLYGONSELECTIONTAG_DEFORMEDSTATEParameter: Fields
POLYGONSELECTIONTAG_FIELDS